An electrical characteristics test of semiconductor devices is performed in such a way as to bring a semiconductor wafer close to a probe card of which a number of contact probes are formed on a wiring board, and thereby bring the respective contact probes into contact with corresponding electrode pads on the semiconductor wafer to input/output a test signal through the contact probes.
When bringing the contact probes into contact with the corresponding electrode pads, after the both reach a state of starting to contact with each other, a process to further bring the semiconductor wafer close to the probe card is performed. Such a process is called overdrive, and a distance of the overdrive is called an overdrive amount. The overdrive is a process to elastically deform the contact probes, and by performing the overdrive, even in the case where there are variations in height among the electrode pads or the contact probes, all of the contact probes can be surely brought into contact with the corresponding electrode pads.
The inventors of the present application proposed, in the previous patent application, a method for improving high frequency characteristics of a contact probe (Patent Literature 1). The contact probe described in Patent Literature 1 has an elastic deformation part including multiple elongate plate-like bodies of which adjacent principal surfaces face each other via a gap. Employing such a configuration makes it possible to shorten the length of the probe to improve the high frequency characteristics of the contact probe while ensuring an overdrive amount and probe pressure.
Also, the inventors of the present application proposed a method for further improving the above-described contact probe to improve current resistant characteristics of the contact probe (Patent Literature 2). In a contact probe described in Patent Literature 2, the above-described plate-like bodies have three-layer structure that sandwiches a conductive layer between stress layers in a width direction thereof. For this reason, current resistant characteristics can be improved while ensuring an overdrive amount, probe pressure, and high frequency characteristics.